DC Microgrid with PV, Battery & Supercapacitor Coordinated Control in MATLAB/Simulink
DC Microgrid with PV, Battery & Supercapacitor Coordinated Control
𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧
A DC microgrid provides an efficient platform for integrating renewable energy sources, energy-storage devices, and DC loads through a common DC bus.
DC Microgrid with PV, Battery & Supercapacitor Coordinated Control
This MATLAB/Simulink model demonstrates the coordinated operation of:
☀️ Solar PV system
🔋 Lithium-ion battery
⚡ Supercapacitor
🔄 DC–DC power converters
🎯 Incremental Conductance MPPT
🎛️ Voltage and current controllers
💡 DC load
The main objective is to maintain the DC bus voltage at 24 V while continuously balancing power among the PV source, battery, supercapacitor, and load.
The model also demonstrates how a supercapacitor can handle fast transient power changes while the battery manages slower and sustained power imbalances.
𝐒𝐲𝐬𝐭𝐞𝐦 𝐎𝐯𝐞𝐫𝐯𝐢𝐞𝐰
The DC microgrid consists of three main energy sources/storage elements connected to a common DC bus.
Component | Interface | Main Function |
Solar PV | Boost converter | Renewable power generation |
Battery | Bidirectional DC–DC converter | Long-term energy storage |
Supercapacitor | Bidirectional DC–DC converter | Fast transient compensation |
DC Load | DC bus | Consumes approximately 4 W |
MPPT Controller | PV boost converter | Extracts maximum PV power |
Voltage/Current Controller | Storage converters | Maintains power balance and DC voltage |
The common DC bus acts as the main point through which generation, storage, and load power are exchanged.
𝐌𝐚𝐢𝐧 𝐒𝐲𝐬𝐭𝐞𝐦 𝐏𝐚𝐫𝐚𝐦𝐞𝐭𝐞𝐫𝐬
Solar PV Parameters
Parameter | Value |
Rated PV power | 10 W |
Open-circuit voltage | 21.9 V |
Voltage at maximum power point | 17.9 V |
Short-circuit current | 0.71 A |
Current at maximum power point | 0.56 A |
A relatively small PV rating is used so that the complete DC microgrid operation can be clearly demonstrated and analyzed.
Battery Parameters
Parameter | Specification |
Battery type | Lithium-ion |
Individual cell/module voltage | 3.6 V |
Number connected in series | 2 |
Main role | Energy balancing and sustained charging/discharging |
Supercapacitor Parameters
Parameter | Value |
Capacitance | 58 F |
Rated voltage | 16 V |
Main role | Transient power support |
DC Microgrid Parameters
Parameter | Value |
DC bus reference voltage | 24 V |
DC load power | 4 W |
Approximate load current | 0.17–0.18 A |
𝐒𝐲𝐬𝐭𝐞𝐦 𝐀𝐫𝐜𝐡𝐢𝐭𝐞𝐜𝐭𝐮𝐫𝐞
The basic energy flow is:
Solar PV → Boost Converter → DC Bus → DC Load
The battery is connected as:
Battery ↔ Bidirectional DC–DC Converter ↔ DC Bus
The supercapacitor is connected as:
Supercapacitor ↔ Bidirectional DC–DC Converter ↔ DC Bus
This configuration allows energy to move in both directions between the storage devices and the DC bus.
𝐖𝐨𝐫𝐤𝐢𝐧𝐠 𝐏𝐫𝐨𝐜𝐞𝐬𝐬
1. Solar PV Generation
The PV panel generates electrical power according to the available solar irradiance.
When irradiance changes:
PV current changes significantly.
PV power changes accordingly.
PV operating voltage remains close to its maximum-power operating region.
The MPPT controller adjusts the converter duty cycle.
The PV source is connected to the common DC bus through a boost converter.
2. Maximum Power Point Tracking
An Incremental Conductance MPPT algorithm is used to extract the maximum available power from the PV array.
The controller continuously monitors:
PV voltage
PV current
Based on these measurements, it determines an appropriate converter operating point.
The resulting control signal is processed by the PWM generator, which produces switching pulses for the boost converter.
This enables the PV system to track changing solar conditions effectively.
3. DC Bus Voltage Regulation
The DC bus reference is fixed at:
24 V
The actual DC bus voltage is continuously measured and compared with this reference.
The voltage controller generates the required current reference for the energy-storage system.
This control structure helps:
Maintain the DC bus close to 24 V
Compensate for PV power variations
Support the DC load
Coordinate battery and supercapacitor operation
𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐒𝐭𝐫𝐚𝐭𝐞𝐠𝐲
The battery and supercapacitor use a coordinated voltage-current control strategy.
Outer Voltage Control
The DC bus voltage is monitored continuously.
The controller determines how much current is required from or absorbed by the storage system.
Battery Current Control
The battery reference current is compared with the actual battery current.
The current controller then produces the required duty-cycle command for the battery's bidirectional converter.
Supercapacitor Current Control
The supercapacitor has a separate current-control path.
Its primary purpose is to react rapidly when sudden power variations occur.
This makes the supercapacitor particularly useful during:
Irradiance step changes
Sudden increases in PV generation
Sudden reductions in PV generation
Short-duration DC bus disturbances
𝐑𝐨𝐥𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐁𝐚𝐭𝐭𝐞𝐫𝐲 𝐚𝐧𝐝 𝐒𝐮𝐩𝐞𝐫𝐜𝐚𝐩𝐚𝐜𝐢𝐭𝐨𝐫
The two storage devices perform different but complementary functions.
Storage Device | Response Characteristic | Main Role |
Battery | Relatively slower | Sustained energy balancing |
Supercapacitor | Very fast | Transient compensation |
Battery
The battery:
Charges when excess PV power is available.
Discharges when PV generation is below load demand.
Helps maintain long-term power balance.
Supports the DC bus during low solar generation.
Supercapacitor
The supercapacitor:
Responds rapidly during transitions.
Supplies short bursts of power when PV power suddenly falls.
Absorbs excess transient power when PV generation suddenly increases.
Reduces the burden of rapid current changes on the battery.
This coordinated operation improves the overall dynamic response of the DC microgrid.
𝐒𝐨𝐥𝐚𝐫 𝐈𝐫𝐫𝐚𝐝𝐢𝐚𝐧𝐜𝐞 𝐓𝐞𝐬𝐭 𝐏𝐫𝐨𝐟𝐢𝐥𝐞
To test the controller under changing renewable generation, the PV irradiance is varied approximately every 2 seconds.
Operating Interval | Irradiance |
Initial condition | 1000 W/m² |
Next level | 800 W/m² |
Next level | 500 W/m² |
Next level | 300 W/m² |
Minimum level | 100 W/m² |
Increasing level | 300 W/m² |
Increasing level | 500 W/m² |
Final increasing level | 800 W/m² |
This profile allows both decreasing and increasing PV-generation conditions to be evaluated.
𝐒𝐢𝐦𝐮𝐥𝐚𝐭𝐢𝐨𝐧 𝐑𝐞𝐬𝐮𝐥𝐭𝐬
The simulation evaluates:
PV voltage
PV current
PV power
DC bus voltage
Load current
Load power
Battery voltage
Battery current
Battery power
Battery SOC
Supercapacitor voltage
Supercapacitor current
Supercapacitor power
PV Response at 1000 W/m²
At full irradiance:
Parameter | Approximate Response |
Irradiance | 1000 W/m² |
PV power | 10 W |
PV voltage | ≈18 V |
PV current | ≈0.51 A |
DC bus voltage | ≈24 V |
Load power | ≈4 W |
Load current | ≈0.17 A |
Since PV generation is substantially higher than the load demand, the available surplus power can be directed toward the energy-storage system.
PV Response at 800 W/m²
When the irradiance decreases to 800 W/m²:
PV output falls to approximately 8 W.
The DC load remains approximately 4 W.
Excess PV energy is still available.
Battery charging can continue.
The supercapacitor responds briefly during the irradiance transition.
DC bus voltage returns quickly to approximately 24 V.
PV Response at 500 W/m²
At approximately 500 W/m²:
PV output becomes approximately 5 W.
Load demand remains approximately 4 W.
Only a small amount of excess PV power remains.
Battery power approaches a low-energy-transfer or near-idle condition.
The supercapacitor provides short transient compensation during the irradiance step.
This operating point demonstrates effective coordination between the two storage devices.
PV Response at 300 W/m²
When irradiance falls to 300 W/m²:
PV output becomes approximately 3 W.
The load still requires approximately 4 W.
PV generation alone cannot meet the load demand.
The battery begins supplying the missing power.
The supercapacitor initially supports the transient.
The DC bus remains regulated close to 24 V.
PV Response at 100 W/m²
At the lowest irradiance level:
PV generation falls to approximately 1 W.
The load remains around 4 W.
A significant power deficit exists.
The battery provides additional energy.
The supercapacitor handles the initial transition.
Storage power increases as required to maintain system balance.
𝐑𝐞𝐬𝐩𝐨𝐧𝐬𝐞 𝐃𝐮𝐫𝐢𝐧𝐠 𝐈𝐧𝐜𝐫𝐞𝐚𝐬𝐢𝐧𝐠 𝐈𝐫𝐫𝐚𝐝𝐢𝐚𝐧𝐜𝐞
The second part of the test increases solar irradiance again.
100 → 300 W/m²
As PV power increases:
Battery discharge requirement decreases.
The supercapacitor absorbs part of the sudden power increase.
A short charging transient appears in the supercapacitor.
300 → 500 W/m²
As PV generation approaches and exceeds load demand:
Battery output decreases further.
Battery operation can transition toward charging.
Supercapacitor transient charging occurs.
The DC bus remains controlled.
500 → 800 W/m²
At higher PV generation:
PV power becomes significantly higher than the 4 W load.
Excess PV power becomes available for storage charging.
Battery power moves into the charging region.
Supercapacitor absorbs fast transient energy.
Stable DC bus operation is maintained.
𝐏𝐨𝐰𝐞𝐫 𝐁𝐚𝐥𝐚𝐧𝐜𝐢𝐧𝐠 𝐁𝐞𝐡𝐚𝐯𝐢𝐨𝐮𝐫
The operating principle can be summarized simply.
PV Condition | Battery Behavior | Supercapacitor Behavior |
PV power much greater than load | Charging | Absorbs transient surplus |
PV power slightly greater than load | Light charging / near idle | Short transient action |
PV power approximately equal to load | Near idle | Minimal steady-state contribution |
PV power below load | Discharging | Supplies transient deficit |
Sudden PV decrease | Supports deficit | Rapid discharge response |
Sudden PV increase | Charging requirement increases | Rapid charging response |
This division of responsibility is one of the major advantages of using a hybrid battery–supercapacitor energy-storage system.
𝐃𝐂 𝐁𝐮𝐬 𝐕𝐨𝐥𝐭𝐚𝐠𝐞 𝐏𝐞𝐫𝐟𝐨𝐫𝐦𝐚𝐧𝐜𝐞
One of the most important results is the regulation of the DC bus.
The reference voltage is:
24 V
During irradiance transitions:
Small temporary voltage deviations may appear.
The battery and supercapacitor controllers respond immediately.
The DC bus quickly returns to the reference level.
The DC load continues receiving regulated power.
This demonstrates the effectiveness of the coordinated storage control strategy.
𝐁𝐚𝐭𝐭𝐞𝐫𝐲 𝐒𝐎𝐂 𝐁𝐞𝐡𝐚𝐯𝐢𝐨𝐮𝐫
Battery state of charge changes according to the power balance.
When PV generation is high:
Excess energy charges the battery.
Battery SOC tends to increase.
When PV generation becomes low:
The battery supplies the power deficit.
Battery SOC tends to decrease.
When PV generation increases again:
Battery discharge decreases.
The battery eventually returns to charging operation.
Therefore, the SOC response confirms correct bidirectional energy transfer.
𝐖𝐡𝐲 𝐔𝐬𝐞 𝐚 𝐒𝐮𝐩𝐞𝐫𝐜𝐚𝐩𝐚𝐜𝐢𝐭𝐨𝐫?
A battery alone can maintain energy balance, but continuously forcing it to respond to rapid power variations may increase electrical stress.
The supercapacitor provides several advantages:
Fast charging and discharging
Rapid transient response
High power capability
Reduced rapid current changes in the battery
Better DC bus voltage regulation
Improved dynamic power sharing
Effective compensation during solar irradiance transitions
The battery therefore handles energy, while the supercapacitor primarily handles fast power variations.
𝐊𝐞𝐲 𝐅𝐞𝐚𝐭𝐮𝐫𝐞𝐬
☀️ 10 W solar PV source
🔋 Lithium-ion battery energy storage
⚡ 58 F supercapacitor
🔄 Two bidirectional DC–DC converters
⬆️ PV boost converter
🎯 Incremental Conductance MPPT
🎛️ Cascaded voltage and current control
⚡ Coordinated battery-supercapacitor power sharing
🔌 24 V regulated DC bus
💡 4 W DC load
🌤️ Variable solar irradiance simulation
📊 Battery SOC monitoring
📈 PV voltage, current, and power monitoring
📉 Storage voltage, current, and power analysis
🔁 Charging and discharging operation
⚡ Fast transient support from the supercapacitor
𝐌𝐚𝐭𝐥𝐚𝐛/𝐒𝐢𝐦𝐮𝐥𝐢𝐧𝐤 𝐂𝐨𝐧𝐭𝐫𝐨𝐥 𝐁𝐥𝐨𝐜𝐤𝐬
The simulation mainly contains:
PV array
Irradiance profile generator
Boost converter
Incremental Conductance MPPT controller
PWM generator
Lithium-ion battery
Battery bidirectional converter
Supercapacitor
Supercapacitor bidirectional converter
DC bus voltage measurement
Current measurement blocks
Voltage controller
Battery current controller
Supercapacitor current controller
Reference-current filtering
SOC measurement
DC load
Power measurement blocks
Simulation scopes
𝐖𝐨𝐫𝐤𝐢𝐧𝐠 𝐒𝐮𝐦𝐦𝐚𝐫𝐲
The complete control process can be understood in six simple stages:
PV generates power according to solar irradiance.
Incremental Conductance MPPT extracts maximum available PV power.
The boost converter transfers PV energy to the 24 V DC bus.
The voltage controller continuously monitors the DC bus.
The battery handles sustained surplus or deficit energy.
The supercapacitor responds rapidly during power transitions.
Together, these controllers maintain stable operation even when PV generation varies significantly.
𝐀𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬
This DC microgrid control concept is useful for studying:
Renewable-energy-based DC microgrids
Solar PV energy-management systems
Battery energy-storage control
Hybrid battery-supercapacitor storage
DC bus voltage regulation
Renewable power smoothing
Standalone DC power systems
Telecom DC power systems
Data-center DC distribution concepts
DC charging infrastructure
Residential DC distribution
Laboratory-scale microgrid studies
Converter control and power-sharing research
MPPT algorithm development
Energy-storage coordination studies
𝐖𝐡𝐨 𝐂𝐚𝐧 𝐔𝐬𝐞 𝐓𝐡𝐢𝐬 𝐌𝐨𝐝𝐞𝐥?
The model is particularly suitable for:
Electrical engineering students
Power electronics learners
MATLAB/Simulink users
Microgrid researchers
Renewable-energy researchers
Energy-storage engineers
Control-system researchers
Engineers studying DC–DC converters
Researchers investigating hybrid energy storage
It provides an easy-to-understand environment for learning how renewable generation and multiple storage technologies can be coordinated within a DC microgrid.
𝐊𝐞𝐲 𝐎𝐛𝐬𝐞𝐫𝐯𝐚𝐭𝐢𝐨𝐧𝐬
The simulation demonstrates that:
PV output follows changes in solar irradiance.
The Incremental Conductance method successfully tracks available PV power.
The 24 V DC bus remains well regulated.
The 4 W DC load receives stable power.
The battery charges when renewable power exceeds load demand.
The battery discharges when renewable generation becomes insufficient.
The supercapacitor mainly responds during rapid transient conditions.
Battery and supercapacitor power sharing changes automatically with operating conditions.
Battery SOC reflects alternating charging and discharging periods.
Hybrid storage improves the transient behavior of the DC microgrid.
𝐂𝐨𝐧𝐜𝐥𝐮𝐬𝐢𝐨𝐧
The DC Microgrid with PV, Battery & Supercapacitor in MATLAB/Simulink demonstrates a practical coordinated energy-management and control strategy for a renewable DC power system.
The solar PV system operates with Incremental Conductance MPPT to obtain the maximum available solar power under changing irradiance. A lithium-ion battery and 58 F supercapacitor are connected through bidirectional converters to support the common 24 V DC bus.
The battery manages sustained energy surplus and deficit, while the supercapacitor provides fast transient compensation during sudden irradiance variations. As PV generation changes from approximately 10 W down to 1 W and then increases again, the storage system automatically changes between charging and discharging operation while maintaining the 4 W DC load.
Overall, the model provides a clear demonstration of MPPT control, DC bus regulation, bidirectional energy transfer, hybrid energy-storage coordination, transient compensation, and renewable power balancing in a DC microgrid.
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